A production method of an optical display device mounted to a conventional liquid crystal display device is conceptually shown in FIG. 7. First in an optical filmmaker, a step produces a long (web-like) sheet material having an optical film as a material roll (#1). The concrete production step is a known production step, and a description thereof will not be given. As the long (web-like) sheet material, for example, there are a polarizing plate material, a retardation plate material, a laminated film material of the polarizing plate and the retardation plate, and the like which are used in a liquid crystal display device. Next, the material roll is slit to a predetermined size (a size in accordance with a size of the optical display unit) (#2). Next, the slit long material is cut to a fixed size in conformity to a size of the optical display unit (#3). Next, a step inspects an outer appearance of a piece of sheet material (an optical film) cut to the fixed size (#4). As the inspecting method, for example, there can be listed up a defect inspection in accordance with a visual observation, and an inspection using a known defect inspection apparatus. The defect means, for example, a dirty in a front face or an internal portion, a scratch, a special twisted defect like a hitting mark generated by biting a contaminant (which may be called as a knick), an air bubble, a contaminant or the like. Next, a step inspects a finished product (#5). The finished product inspection is an inspection in accordance with a quality standard having a severer non-defective determination than the outer appearance inspection. Next, a step works end faces in four sides of the sheet material of the piece of sheet material (#6). This step is carried out for preventing an adhesive or the like from running over from the end faces during transport. Next, a step cleanly packages the piece of sheet material under a clean room environment (#7). Next, a step packages for transport (a transport package) (#8). The piece of sheet material is produced as mentioned above, and is transported to a panel processing manufacturer.
In the panel processing manufacturer, a step dismounts the package of the piece of sheet material transported (#11). Next, a step inspects an outer appearance for inspecting the scratch, the dirt and the like generated at a time of transporting or dismounting the package (#12). The piece of sheet material which is determined as the non-defective by the inspection is fed to the next step. There is a case that the outer appearance inspection is omitted. An optical display unit (for example, a glass substrate unit in which a liquid crystal cell is enclosed) to which the piece of sheet material is bonded is previously produced, and the optical display unit is cleaned before the bonding step (#13).
A step bonds the piece of sheet material and the optical display unit (#14). A release film is peeled off from the piece of sheet material while leaving a pressure-sensitive adhesive layer, and it is bonded to one face of the optical display unit by using the pressure-sensitive adhesive layer as a bonding face. Further, it can be bonded to the other face of the optical display unit in the same manner. In the case of bonding to both the faces, the structure may be made such that the optical films having the same construction are bonded to the faces of the optical display unit, or the structure may be made such that the optical films having different constructions are bonded thereto. Next, a step carries out an inspection of the optical display device in the state in which the optical film is bonded and a defect inspection (#15). The optical display device which is determined as the non-defective in this inspection is fed to a mounting process (#16). On the other hand, a reworking process is applied to the optical display device which is determined as a defective (#17). In the reworking process, the optical film is peeled off from the optical display unit. The optical film is newly bonded to the reworked optical display unit (#14).
In the case of manufacturing a piece of sheet material in the optical film maker as mentioned above, there has been proposed a method of previously detecting a defect of the material roll, and printing a position information of the detected defect on the material roll in a form of a bar code, or storing the position information in a storage device (Patent Documents 1 and 2). In this method, it is possible to remove the portion including the defect in the polarizing plate from the manufacturing line by punching the polarizing plate based on the bar code or the position information read from the memory device.
In the production step mentioned above, since the optical film maker and the panel processing manufacturer exist in the separate places, the end face working, the packaging of the piece of sheet material, the package dismounting and the like are particularly necessary steps. However, there are a problem of a production cost increase caused by multiple steps, a problem of the scratch, the dust, the dirt and the like generated by the multiple steps and the transport, a necessity of the inspection step caused thereby, and a problem that it is necessary to store and manage many kinds of sheet materials as a stock.
As a method of solving the problems, there has been proposed Japanese Patent Application Laid-Open (JP-A) No. 2007-140046 (Patent Document 3). In accordance with this invention, the structure is provided with a supply portion pulling out and supplying a long sheet material from a material roll around which the long sheet material having an optical film corresponding to a member of an optical display device is wound, a detection portion detecting a defect of the long sheet material pulled out by the supply portion, a cutting work portion cutting the long sheet material based on a result of detection of the detection portion and working to an individual sheet material, a transfer portion transferring the sheet material cut by the cutting work portion for a bonding work, and a bonding work portion bonding the sheet material transferred by the transfer portion and an optical display unit corresponding to a member of an optical display device, and these portion are arranged on a continuous production line. In the structure mentioned above, it is possible to directly cut the long sheet material having the optical film into a desired size, and to bond the cut sheet material to the optical display unit. Accordingly, it is possible to directly package the long sheet material wound around the material roll so as to deliver, in place of the conventional step which stamps the long sheet material, tightly packages the stamped sheet material, and delivers to the panel processing manufacturer.